Cell-free membranous preparations of the magnum section of the chicken oviduct catalyze the mannosylation of several membrane glycoproteins. This process involves glycolipid intermediates: mannosyl-phosphorl-dolichol and a lipid-linked oligosaccharide. This proposal concerns the changes that the glycosyl transferase system undergoes during differentiation of the oviduct. Since cell-surface glycoproteins may be involved in cell-cell interactions the system under study may provide insight into the role glycoprotein biosynthesis plays in cell recognition. Membrane preparations of immature oviduct will be assayed for the various transferase activities. If they are not present, or are present at low levels, attempts will be made to induce the activity by administering steroid hormones to chicks before sacrifice. Comparisons of the proteins glycosylated by extracts of immature and mature oviducts will be made since it is possible that the glycosyl transferase system is constitutive but the final glycoprotein products are different in each case. Another aspect of this study is to learn whether or not the membrane glycoproteins are exposed on the cell surface. This will be approached by using fluorescent labeled antibodies. The glycoproteins will be solubilized by detergents, choatropic agents, etc. and purified by standard techniques. Rabbit antibodies will be prepared against the purified glycoproteins. By using fluorescent labeled goat anti-rabbit gamma-globulin, attempts will be made to determine if the glycoproteins are exposed on the cell surface and if possible which cell types in the oviduct biosynthesize them.